Quiet strander

ABSTRACT

For relatively quiet operation a strander is provided with a streamlined bow formed by joining two reinforced plastic members having elongated cross sections and being grooved to allow a passageway between them for the strand.

United States Patent [191 Madalozzo et al.

[ Feb. 26, 1974 QUIET STRANDER [75] Inventors: David D. Madalozzo, Tarboro, NC; Charles E. Koons, Freeman; Michael E. McGuire,. Adrian, both of Mo.; Earl D. Jones, New York, NY.

[73] Assignee: The Anaconda Company, New

York, NY.

22 Filed: Feb. 16, 1973 21 Appl. No.: 333,105

[52] U.S. Cl 57/58.52, 57/58.67, 57/58.7 [51] Int. Cl. D07b 3/12, DOlh 7/90 [58] Field of Search 57/58.52-58.57,

[56] References Cited UNITED STATES PATENTS Blaisdell 57/58.7

3,142,952 8/1964 Krafft et al. 57/58.7 X 3,147,580 9/1964 Blaisdell et al. 3,348,369 10/1967 Burr 57/58.7

Primary Examiner.l0hn Petrakes Attorney, Agent, or Firm-Victor F. Volk [57] ABSTRACT For relatively quiet operation a strander is provided with a streamlined bow formed by joining two reinforced plastic members having elongated cross sections and being grooved to allow a passageway between them for the strand.

8 Claims, 5 Drawing Figures PATENTEDFEB26 1974 5 i 11}... E M

QUIET STRANDER In the twisting together of insulated wires or other strands to form a twisted pair or other helically assembled cable-like member, a class of apparatus is known in which one or more of the strands are rapidly rotated around a supply of the strand that is supported on a non-rotating cradle. Usually, the supply is wound on a reel and the strand being rotated is supported by a curvilinear bow that is mounted in bearings to straddle the cradle and rotate around it. The reel in the cradle may be the take-up reel for the twisted strands, in which case the pay off reel or reels for the strands are fixedly mounted exteriorly of the rotating bow. The reel may be the supply reel for one strand being twisted with one or more other strands, in which case the take-up reel for the twisted strands, and a supply of the other strands are fixed exteriorly of the rotating bows. Again, all the strands to be twisted may be supported on one or more reels in the cradle while only-the take-up reel is mounted exteriorly of the bow. An example of a strander wherein the take-up reel is mounted in the era dle and the strand supply reels are mounted exteriorly of the bow, is described in Burr U.S. Pat. No. 3,348,369

the teachings of which are incorporated herein by reference. Modern bow-type twinners or stranders are operated at very high speeds such that the bows, of which there have been two, for dynamic balance, rotate at 1,000 r.p.m. or faster and create a severe problem of noise pollution, particularly when there are a large number of the machines in a confined area. A single conventional bow-type twinner operating at 1,000 r.p.m. had a noise level of 93 dBA. (The term dBA refers to decibels on the A scale defined in USA Standard for Sound Level Meters, S l.4, I961.)

SUMMARY We propose, by our invention, to reduce the noise level of bow-type stranders. This has been accomplished, as shall be explained, by changing the structural configuration and material of construction of strander bows, but by using our new how we also discovered that we had eliminated the need for two bows, which reduced the noise level even further. Our improved apparatus was found to have a further advantage of reducing the hazard to property. We have made improvements in stranding apparatus of the type that comprises a cradle supported between two bearings and has at least one reel mounted on the cradle and also has a bow that is mounted in the bearings to rotate around the cradle on a horizontal axis. The improvement comprises a bow which comprises a fiber reinforced synthetic polymeric member having a leading and a trailing edge and being elongated in section so that the width of the member substantially exceeds its thickness, preferably in a ratio of at least 3 to 1 and more preferably 4 to l.'The trailing edge and, preferably also the leading edge of the bow member is tapered. In preferred embodiments the bow member comprises two strips comprising a tangential interface which may extend from the leading to the trailing edge, with the passageway being defined in theinterface.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows a side view of the apparatus of our invention.

FIG. 2 shows a plan viewof anouter strip of a bow of our apparatus.

FIG. 3 shows a plan view of an inner strip-of a bow of our apparatus.

FIG. 4 shows a section throughthe lines 4--4 of FIG. 1.

FIG. 5 shows a section of another embodiment of the bow of our apparatus. 7

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIG. 1 an apparatuswith the improvements of our invention is indicated generallybythe numeral 10. This apparatus comprises a twinner of the type where the insulated conductors ll, 12 to be twisted or stranded together, referred to in theart as being twinned, are paid from reels, not shown, mounted at fixed stations into ashort hollow shaftturning in bearings 14, 16 and rotatably supporting an end plate 17. The shaft 13 is driven by a timing belt 18 from a long drive shaft, not shown, from which is also driven, by means of a timing belt 20, a short shaft 19, supporting another end plate 21 to rotate at the same speed as the plate 17. The shaft 19 rotates in bearings 22, 23. Between the bearings 16, 22 there is mounted a cradle 24 on stub shafts 26, 27 thatpermit it to remain horizontal while the plates 17, 21 rotate. A take-up reel 28 traverse guides 29 reel drive 31 and capstans 3,2, 33 are mounted in the cradle 24. The plate 17 firmly supports a bracket 34, and the plate 21 firmly supports an. opposite bracket 36 which, between them, support a bow 37.

The bow 37 is comprised of an outer strip38 (FIGS. 2 and 4) of glass reinforced plastic and an inner strip 39 which come together in an interface 41 tangential to the circle of rotation of each point of the bow. With glass reinforcing a number of thermoplastics such as nylon, polycarbonate, ABS, polyester and polyvinyl chloride can be used for the strips 38, 39 although we prefer a thermoset such as polyester, epoxy or phenolic. All of these materials are several times lighter than steel and their lightness eliminates, in actual operation, the need for an oppositely placed bow to balance the how 37. A groove 42 extends almost the entire length of the strip 38 and a matching groove 43 extends the full length of the strip 39. These grooves combine to form a passageway 44 at the interface 41 for the conductors 1 l, 12 which are passed into the passageway44 from a guide sheave 46 and leave it over a guide sheave 47 paying into the capstan 33. The strip 38 is bolted to the bracket 34 by means of bolt holes-48, 49. and to the bracket 36 by means of bolt holes 51, 52. The inner strip 39 is bolted or riveted to the strip 38 through the matching holes 53, 53a; 54, 54a; 56, 56a; 57,57a when the apparatus 10 is operating so that the bow 37 turns into the plane of the paper as seen in FIG. 1, the bow 37 has a leading edge 58 and a trailing edge 59 which are tapered for the greater length of the strips at angles of about 30. The tapered sections are terminated at the points 61, 62 to provide greater strength in the end areas of the strips comprising the bolt holes. The width of the bow 37 from the end 58 to the end 59 is about four times the thickness from a surface 63 to asurface 64. This elongated sectional shape plus the tapering of the trailing edge 59 provides a streamlining effect that is further enhanced by the taperingof the leading edge 58 and has resulted in an unexpectedly large reduction in the noise produced by the apparatus, as shall be described in detail. Dimensions of a particularly successful bow used in our invention comprised of a strip 38, 71 inches long, 2 inches wide, and 54 inch thick, and a strip 39, 51 inches long, 2 inches wide, and 3/16 inch thick. The length of the bow 37 exceeds, of course, the horizontal distance between the brackets 34, 36 to allow for the outward curvature or bowing that permits the bow 37 to clear the cradle 24 and reel 28.

In FIG. 5 we have shown an alternative embodiment of our bow, indicated by the numeral 66 wherein an outer reinforced plastic strip 67 is recessed at 68 to receive an inner plastic strip 69. The strip 67 is grooved at 71 and the strip 69 is grooved at 72, the two grooves combining to form a passageway for the strand. Bows of conventional stranders have commonly been constructed of steel such as cylindrical steel tubing since the rotation of the strander imparts centrifugal tensile stresses to the bow. We have found, however, that fiber glass reinforced polymeric compositions have sufficient tensile strength to resist these forces. Indeed, in the construction of FIG. 5, although we prefer to reinforce both the strips 67 and 69 the latter, being supported during operation by the former, may comprise an unreinforced plastic or other strip. Additionally, if the strand being processed is sufficiently small, the passageway 44 may be formed by a groove in only one, rather than both of the strips. Although the tensile strength of reinforced plastic is high its impact strength does not approach that of steel and this has proven to have an unexpected safety advantage in our apparatus since our reinforced plastic bows will shatter upon striking an obstacle, such as a loose reel lock, without further damage to the machine or surrounding area. The apparatus is enclosed in a sheet-steel cylindrical hood 73 of conventional design comprising a sliding cover 74 which can be closed when the apparatus is in operation.

Our improved apparatus has effected an unexpectedly high reduction of the noise level of a stranding machine. Prior to the present invention an effort was made to reduce the noise of the apparatus by substituting fiber gears for metal gears. At 1,000 r.p.m., however, both metal and fiber gear operation produced a noise level of 93 dBA. In Table I we show the relation of noise level to speed with an apparatus using conventional inch diameter steel twin bows.

TABLE I Speed, r.p.m. Noise, dBA 500 79 600 82 700 85 800 90 900 91 1000 93 In Table II we show the change effected in noise level by using asingle conventional steel bow of 7% inch diameter and applying a lead sheath over the hood.

TABLE II Speed, r.p.m. Noise, dBA. 500 75 600 79 700 83 800 85 900 86 1000 89 In Table III we show the effect on noise of reducing the bow diameter to three-eighths inch. Other features are the same as those of Table II. I

TABLE III Speed, r.p.m. Noise, dBA 500 74 600 77 700 80 800 82 900 86 1000 88 The results shown in Tables II and III having indicated that the lead sheathing, besides being expensive, was ineffective as a noise suppressant, the reinforced plastic bow of FIG. 4 was substituted for the steel bows, and the apparatus operated with fiber gears but without lead sheathing. The results are shown in Table IV.

TABLE IV Speed, r.p.m. Noise, dBA 500 68 600 70 700 73 800 76 900 78 1000 83 The dramatic drop of 5 dBA between Tables III and IV at 1,000 r.p.m. was surprising in the light of the small changes in dB level resulting from our other efforts for improvement. To this must be added an improvement of several dB obtained by using only one bow, which is practicable in continuous operation only with our new light-weight bow.

The operation of our apparatus is conventional. In the illustrated embodiment the strands to be twisted are initially threaded through the shaft 13, around the sheave 46 into and through the passageway 44 to the sheave 47, around the capstans 33, 32 through the traverse guides 29 to the take-up reel 28. The sliding cover 74 of the hood 73 is closed and the apparatus started with rotation of the reel 28 and capstans 33, 32 syncronized to the speed of rotation of the bow 37 around the cradle 24.

The foregoing description has been exemplary rather than definitive of our invention for which we desire an award of Letters Patent as defined in the appended claims.

We claim:

I. In a stranding apparatus comprising a cradle supported between two bearings, at least one reel supportably mounted in said cradle, a bow mounted in said bearings to rotate on a horizontal axis around said cradle, the improvement wherein said bow comprises:

A. a fiber reinforced synthetic polymeric member having a leading and trailing edge, said member being elongated in section thereby having a width substantially exceeding its thickness,

B. said member defining a lengthwise interior passageway wherein strand is rotated around said reel, and

C. said trailing edge being tapered; said improved bow substantially reducing the noise level of operation of said apparatus.

2. The apparatus of claim 1 wherein said leading edge is tapered.

3. The apparatus of claim 2 wherein the width to thickness ratio of said member exceeds three.

6 4. The apparatus of claim 1 wherein said member thickness ratio of said member exceeds three. comprises two strips comprising a tangential interface, 7. The apparatus of claim 1 wherein said fiber comsaid passageway being defined in said interface. prises glass' 5. The apparatus of claim4wherein said interface ex- 8. The apparatus of claim 1 wherein the width to tends from said leading to said trailing edge. 5 thickness ratio of said member exceeds three.

6. The apparatus of claim 5 wherein the width to 

1. In a stranding apparatus comprising a cradle supported between two bearings, at least one reel supportably mounted in said cradle, a bow mounted in said bearings to rotate on a horizontal axis around said cradle, the improvement wherein said bow comprises: A. a fiber reinforced synthetic polymeric member having a leading and trailing edge, said member being elongated in section thereby having a width substantially exceeding its thickness, B. said member defining a lengthwise interior passageway wherein strand is rotated around said reel, and C. said trailing edge being tapered; said improved bow substantially reducing the noise level of operation of said apparatus.
 2. The apparatus of claim 1 wherein said leading edge is tapered.
 3. The apparatus of claim 2 wherein the width to thickness ratio of said member exceeds three.
 4. The apparatus of claim 1 wherein said member comprises two strips comprising a tangential interface, said passageway being defined in said interface.
 5. The apparatus of claim 4 wherein said interface extends from said leading to said trailing edge.
 6. The apparatus of claim 5 wherein the width to thickness ratio of said member exceeds three.
 7. The apparatus of claim 1 wherein said fiber comprises glass.
 8. The apparatus of claim 1 wherein the width to thickness ratio of said member exceeds three. 